Use uvloop as asyncio event loop

[sbellem]

That would for (I/O) optimization reasons if needed.

uvloop is a fast, drop-in replacement of the built-in asyncio event loop. uvloop is implemented in Cython and uses libuv under the hood.

-- https://github.com/MagicStack/uvloop

If the current state of the project does not require such optimization, this issue may be closed.